The US national team suffered its first loss under head coach Jurgen Klinsmann after a disappointing effort against Costa Rica on Friday night at the Home Depot Center in Carson, California.

Despite clearly dominating the flow of play throughout most of the game, the US was unable to generate a shot on goal until midway through the second half. Costa Rica did just enough to escape with the 1-0 victory, in spite of numerous great opportunities and build-ups by the US that yielded nothing but exasperated gasps from the crowd and clenched teeth from US players.

"Obviously, bad result, you never like to lose a game, but a very good performance," said Jurgen Klinsmann with an uneasy smile. "The first 30 minutes was top, then we had a down period 10 minutes before half time. The players are beginning to learn that if you want to maintain a very high tempo through 90 minutes, it's difficult."

With the pressure of his US coaching debut against archrival Mexico in the books, Klinsmann sent out a similar squad against an always tough Costa Rican squad. The US came out attacking, displaying marked cohesiveness, and it showed in the way they connected, dominating Costa Rica thoroughly in the first half hour.

The best opportunity came in the 6th minute, when Landon Donovan blasted a shot just right of the goal as he blazed into the box after a great series of passes between Brek Shea, Jozy Altidore, and Donovan.

Donovan missed another opportunity to put the US up in the 22nd when his free kick from just beyond the top of the box whizzed past the top left corner of Keylor Navas' goal.

Shea looked sharp early on while trying to hook up with Altidore. Although he was able to create some space for himself with a few nifty moves, Shea was shadowed on almost every play and never really got going like he would have wanted to.

"I think I did some things good and some things bad," Shea said. "I think it's more about still getting used to playing with the guys. [Klinsmann] wants us to play with confidence and have fun-play soccer, move the ball, not just kick the ball and run around. When I'm in the attacking third, I feel I have complete freedom."

Although the US continued to pile on pressure, as halftime drew nearer, the team began to show signs of weariness and Costa Rica began to go on forays into the US half.

In the 45th minute, Altidore sent a through-ball to Donovan, who sprinted from midfield toward the Costa Rican net. However, instead of pushing toward the goal, Donovan opted to pass back to Altidore, who was covered.

Nevertheless, it was Costa Rica who registered the first two shots on goal, in injury time. With the US attack slowing to a sputter, Costa Rica begun to get more involved on the counterattack and found themselves in their attacking third, almost scoring on two dangerous shots on goal.

It took a full outstretched Tim Howard to knock Alvaro Sanchez' blistering shot over the top of the crossbar right before the end of the half.

While the final 10 minutes of the half were difficult for the US, Klinsmann saw this as a learning experience for his players.

"I want them to go through those down periods," he said. "We saw players getting tired-they were struggling. But, they need to learn to go through those minutes. They need to fight their way through it. If you keep that tempo up, sooner or later, you will put away those chances.

"We worked hard at that during the week. Throughout the games, they will have these moments where they can't keep it anymore. They don't have that in their systems yet. That will be a process we will have to go through, long term," he added.

As has been customary of recent US matches, the second half was an altogether different story. While the US still maintained some hegemony at midfield, Costa Rica begun to go on deeper runs and spent more time with the ball.

With the mostly pro-American crowd of 15,798 pushing them on, the US tried to get things going up top again, but it was Costa Rica who threatened, letting loose with another shot on Howard's goal in the 59th.

Still recovering from a hamstring injury, Klinsmann limited Altidore to 63 minutes, subbing in Juan Agudelo.

Despite the injection of energy to the front line, the inevitable happened in the 65th minute and Costa Rica finally scored, catching the US defense flat-footed on a counterattack.

Alvaro Saborio rushed toward Howard's goal from the right side and sent a through-ball to Michael Barrantes, who fired a shot toward the net. Howard made an outstanding save, falling back in the process. The loose ball found a wide-open Rodney Wallace, who headed the shot toward the goal, where it was deflected but still found the ceiling of the net.

From that moment on, the US turned up the pressure, working hard to crack the Costa Rican bunker that materialized at the other end of the field.

"It's difficult when a team like Costa Rica goes one goal up because they lock it down and put 9 men around the box," Klinsmann admitted.

There was a visible sense of urgency from the US, but, it wasn't until the 71st minute that the US finally got a clear shot on goal, albeit a long-range shot by Jose Torres that was stopped by a diving Navas.

As the game neared the end, tempers flared. Despite both teams having made a pledge to honor FIFA's Fair Play initiative, there were fouls aplenty, with the Ticos racking up 27 fouls to the USA's 12. Referee Jose Molina handed out a total of six yellow cards, three to each team, in what was at times a scrappy affair.

In the end, the Ticos were able to stymie the US attack and exited the field with their heads held high, leaving behind a bemused US squad and coach. The Ticos, being the more aggressive of the two, did whatever they could to disrupt the USA's flow of play and it worked.

Klinsmann felt this is something the US needs to work on, especially in close games.

"You gotta be more determined, greedy for that goal. Maybe it'll take more nastiness," said Klinsmann laughing. "Costa Rica did that very well; on the one-on-one battles, they were nasty. They tried to interrupt our rhythm. We need to be more hungry in those moments and finish off our chances."

The players, echoed Klinsmann's feelings about the game, bemoaning the loss, but pointing out the positives.

"I think we did well," Edu said. "The first half we played well. The final ball was off just a bit. If we play against Belgium the same way we played in the first half, we'll have them on their toes."

Meanwhile, Agudelo took a moment to peer into the not so distant future regarding the direction of the team under the new coach.

"I think that once we get used to [Klinsmann's] style, we'll be a really good team," he said. "He brings a style that looks to accommodate the players."

Although a smiling Klinsmann reminded the press corps that this is all still a work in progress, it wasn't enough to mask his disappointment in the result. While on the surface, the team is responding well to his coaching style, it is quite apparent that success won't come easy.

However, if all goes according to Klinsmann's plans, the US will emerge from this period of uncertainty stronger than ever, or at the very least be able to field a team of long-distance runners.